The Mariana Trench, located in the western Pacific Ocean, is the deepest known oceanic trench on Earth. Stretching approximately 1,580 miles (2,550 kilometers) long and 43 miles (69 kilometers) wide, it plunges to immense depths. At its lowest point, Challenger Deep, the trench reaches about 36,070 feet (10,994 meters) below the ocean surface. This extreme environment is characterized by crushing pressures, perpetual darkness, and near-freezing temperatures.
The Exclusive Club: Who Has Reached the Deepest Point?
Reaching Challenger Deep, the deepest point of the Mariana Trench, is an exceptionally rare achievement, with only a handful of human-occupied descents. Fewer individuals have visited this abyss than have ascended Mount Everest or traveled to space. As of late 2024, fewer than 30 people have successfully made the journey to the trench’s deepest point in human-occupied submersibles.
The first human-occupied expedition to Challenger Deep occurred on January 23, 1960, aboard the U.S. Navy bathyscaphe Trieste. Oceanographer Jacques Piccard and U.S. Navy Lieutenant Don Walsh piloted the vessel. It took another 52 years for the next human-occupied descent. On March 26, 2012, filmmaker and explorer James Cameron piloted the Deepsea Challenger submersible to the bottom, becoming the first person to make a solo journey to Challenger Deep.
More recently, the Five Deeps Expedition expanded the number of visitors to the trench. Victor Vescovo, a private explorer, completed the first of several descents in his submersible, Limiting Factor, on April 28, 2019. Subsequent dives by Limiting Factor throughout 2019 and into 2020 allowed other individuals to reach Challenger Deep, including astronaut Kathryn Sullivan, the first woman to reach the deepest point, and explorer Vanessa O’Brien.
The Journey to the Abyss: How Explorers Descend
Descending into the Mariana Trench presents engineering challenges due to extreme conditions. The most significant hurdle is the immense pressure, which can exceed 1,000 times the atmospheric pressure at sea level. To withstand this, submersibles are constructed with robust materials, such as high-strength steel or titanium, often shaped into spherical pressure hulls.
Navigating the perpetual darkness and near-freezing temperatures also requires advanced technological solutions. Submersibles are equipped with powerful external lights for visibility and sophisticated sonar systems for mapping the seafloor. Life support systems must be designed to provide breathable air and regulate cabin temperature.
Each submersible used for these expeditions features unique design elements to manage descent and ascent. The Trieste was a bathyscaphe, using gasoline for buoyancy and iron shot for ballast. The Deepsea Challenger was designed with a unique vertical orientation for rapid descent and ascent. The Limiting Factor is a full ocean depth-rated submersible, utilizing ceramic spheres for buoyancy and advanced battery systems for power.
Unveiling the Deep: Why Explore the Mariana Trench?
Exploration of the Mariana Trench expands humanity’s understanding of our planet and the limits of life. The unique ecosystems found within the trench host a variety of extremophiles, organisms adapted to survive under crushing pressures, no light, and scarce nutrients. Studying these life forms provides insights into the potential for life in other extreme environments, including extraterrestrial settings.
The trench also holds geological importance, offering a natural laboratory to study plate tectonics, seismic activity, and the processes that shape Earth’s crust. Scientific instruments deployed during these expeditions collect data on the trench’s geology, chemistry, and hydrology, contributing to models of Earth’s interior. This research helps scientists understand how deep-sea trenches are formed and their role in global geological cycles.
Technological advancements from deep-sea exploration have broader applications beyond oceanography. Innovations in materials science, robotics, and life support systems developed for submersibles can benefit various industries, from offshore energy to medical technology. The pursuit of understanding the Mariana Trench inspires future generations to explore the unknown.